UK hospitals will stop selling confectionary containing over 250 calories in a bid to combat rising rates of obesity and type 2 diabetes.

NHS chief executive Simon Stevens has instructed hospital shops to replace supersized chocolate bars and 'grab bags' of sweets with healthy foods. Most standard sized chocolate bars are below 250 calories and these will still be sold by hospital shops.

The crackdown is steered towards reducing junk food consumption by patients, visitors and also NHS staff. Over half of the NHS 1.3 million employees are estimated to be either overweight or obese.

Promotions and junk food advertising have already been banished on NHS premises, with healthier food and drink options supposed to be accessible. Additionally, NHS organisations have been encouraged to sell less of the high-calorie items - such as 400-calorie-plus sandwiches and meals as well as drinks with over 5g of sugar per 100ml - through financial incentives.

Stevens said: "The NHS is now stepping up action to combat the 'supersized' snack culture which is causing an epidemic of obesity, preventable diabetes, tooth decay, heart disease and cancer. In place of calorie-laden, sugary snacks we want to make healthier food an easy option for hospital staff, patients and visitors."

The ban also comes on the back of the Healthier Choices programme, which has been introduced by the Royal Voluntary Service, an operator of shops and cafes as well as trolleys in hospitals.

Chair of the National Obesity Forum Tam Fry said: "A 250kcal chocolate bar is a quite sufficient snack for anybody and his limits on sugary drinks, fat and savoury items are probably the severest that [Stevens] can get away with for the time being."